Hello! Thank you for your question. I will be assisting you today.
What's the exact model of your ereader? How old is it?
You can get a kindle charger, that you can plug in an electric outlet:http://www.amazon.co.uk/PowerFast-Charger-Accelerated-Charging--readers/dp/B006GWO6JW/ref=sr_1_1?ie=UTF8&qid=1381482545&sr=8-1&keywords=kindle+charger
Or you can set the computer not to go to sleep.
Let me get the instructions for you how to set the computer not to power off / go to sleep
Open Power Options by clicking the Start button, clicking Control Panel, clicking System and Security, and then clicking Power Options.
On the Select a power plan page, click Change plan settings next to the selected plan.
On the Change settings for the plan page, click Change advanced power settings.
On the Advanced settings tab, double-click Sleep, double-click Sleep after, and then do one of the following:
If you're using a laptop, click On battery or Plugged in (or both), click the arrow, and then click Never.
If you're using a desktop computer, click Setting, click the arrow, and then click Never.
Double-click Hibernate after, and then do one of the following:
If you also want the display to stay turned on, double-click Display, double-click Turn off display after, and then do one of the following:
Click OK, and then click Save changes.
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